1. Technical Field
The present invention relates to a linear vibration motor.
2. Description of the Related Art
A general vibration motor, which is a component converting an electrical energy into mechanical vibration using a principle of generating electromagnetic force, is mounted in a mobile communication terminal, a portable terminal, and the like, to be used for silently notifying a user of call reception.
Further, in a situation in which small-sized and high quality components are required in a mobile communication terminal in accordance with the trend in which a multi-functional mobile communication terminal has been prominent due to the rapid expansion in wireless communication and mobile phone markets, performance and a technology of a vibration motor has also been developed daily in order to overcome a disadvantage of an existing product and significantly improve quality.
In addition, as the release of a cellular phone having a large-sized liquid crystal display (LCD) screen has rapidly increased in recent years, a touch screen scheme has been used. As a result, the vibration motor has been used to generate vibration at the time of touch, such that the demand thereof has increased.
Meanwhile, performance particularly required in the vibration according to the touch of the touch screen is as follows. First, as the number of vibration generation according to the touch becomes larger than that of vibration generation at the time of call reception, an operation lifespan time needs to increase. Second, in order to allow users to feel the vibration at the time of touch, a response speed of the vibration needs to increase in accordance with a touch speed of the screen.
A linear vibration motor, which is a vibration motor capable of satisfying the above-mentioned characteristics, has a resonant frequency determined by a spring and a vibrator part connected to the spring and is excited by electromagnetic force to thereby generate vibration. In addition, the electromagnetic force is generated by the interaction between a magnet of the vibrator part and a current applied to a coil of a stator part and having a predetermined frequency.
In the case of the linear vibration motor configured as described above, as the vibrator part moves vertically, it collides with a case or a bracket to thereby cause touch noise. In order to prevent the above-mentioned problem, a ring shaped band has been formed by applying MF or a damping material (a rubber, Poron, or the like) has been used.
However, when the MF is used, the MF is made of liquid to be scattered to the surroundings at the time of excessive impact, such that it is separated from its position. Therefore, a damping function is weakened, such that noise is generated at the time of a vibration operation. In addition, the damping material such as the rubber, the Poron, or the like, occupies a predetermined volume, such that it may not be easily disposed in a limited space and a degree of freedom in design is degraded.